[dv657172]

Question 1 - Car has a Pontiac dash tach installed by a previous owner. How would a dealer have routed the wire from the coil through the firewall? My 72 Shop Manual shows a hole between the fuse block and DS fender but there isnt one there. A previous owner used an opening just below accelerator cable (see 1st pic, brown wire) but doubt that that is correct

Question 2 - I have the correct wire harness from the coil but the previous owner installed a jumper wire between harness and tach (see 2nd pic). Does anyone make an eyelet that can be attached to the back of the tach with a blade terminal to go into the harness?

[OG68]

This is my 68. I assume (yeah I know) the 71 would be similar.







The tach should have a spade terminal, not an eyelet. It's would be easier to add the spade terminal to the eyelet post then to create a special jumper.





This is a clock, tach would be similar

[dv657172]

OG68

I know the tach needs the spade, the previous owner put the jumper in. My question is where can I find a spade terminal to put on the tach?

Nice looking firewall on your 68. There is no hole in the location on my firewall like the manual shows or yours has that I can see. Maybe I need to look again??
Did they all come with a hole in that location or was it based on the options ordered. My rally guages originally came from the factory with a clock which was replaced sometime in the past with the tach.

[OG68]

Del Mar Wire has the spade. Electrical supply houses near you may also.

https://www.delmarwire.com/terminals...sc-connectors/

71 service manual shows an opening for the tach lead in the same area as my 68. My 68 didn't have any options beyond a remote mirror and a radio but the accessory opening was still there with a rubber plug.

[Greg Reid]

It won't be so obvious if you have a power brake booster.

[dv657172]

OG68 - thanks for website to get correct terminal

OG68 & Greg - car does have a power booster but for the life of me I dont see any hole. I also have a 72 and dont see one on that car either

Attached a pic of above fuse block, not the best pic.

[Greg Reid]

Hmmm... I don't see it either. My car is also a '68. Arlington build. Strange that they would have changed something like that rather than just sticking a plug in it if they didn't require it any more. Maybe when they got rid of the hideaways?

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[dv657172]

I have one like that but in the middle of the firewall. I was trying to be correct in routing the wire as per a 72 shop manual (assuming 71 is the same) which shows the location you have but beginning to wonder if manual is incorrect....

Pic of one in the middle attached

[Greg Reid]

'68 actually has that one also. I'm betting that brake booster hole is a hideaway headlight thing and a hood tach passage also.. Your grommet would be a more logical place for tach lead anyway since it's right there at the coil.

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[OG68]

Is there a dimple in that area? May require drilling a 1.25" hole.

Do you have a 71 assembly manual? Check the firewall drawings in section 1 for dimple / hole locations.

Drawings from 69 and 70 assembly manuals

[dv657172]

I dont have an assembly manual but looks like a good thing to have. Will take a look for dimple area this evening

[dv657172]

No dimples in that area that I can find

[OG68]

Take another look here.

Depending on how much work you want to do, you will probably need to remove the booster and MC just to get enough room to drill the hole. If you're willing to do that I'd suggest sanding down that area and the dimples will show theirselves as low spots.

[dv657172]

Good eye OG68 there is a small indentation in that spot you pointed out. Your pre-paint picture was also very helpful.

IF we pull the engine over the winter, to replace a rear main seal and dipstick tube, I will probably remove the power booster and drill it out.

Thanks for all your help, pics, drawings and patience on my inquiry and Greg's help too! Very much appreciated.

DV